A vehicle can be equipped with deployable safety devices designed to reduce injury to a pedestrian struck by the vehicle. For example, the vehicle may be equipped with one or more pedestrian air bags and/or a device for changing the inclination angle of the hood. Since the initial point of impact is nearly always the bumper, many deployment systems include one or more pressure or deformation responsive strips disposed in or on the front and/or rear bumpers. See, for example, the U.S. Pat. No. 6,784,792 to Mattes et al., which suggests the use of wire strain, piezoelectric film, magneto-electric, magneto-resistive or optical sensor elements on the bumper fascia. In another approach disclosed in the U.S. Pat. No. 6,607,212 to Reimer et al., light energy scattered within a block of translucent polymeric foam disposed between the bumper fascia and a rigid bumper frame element is detected to form a measure of crush experienced in a collision.